HostPhot: global and local photometry of galaxies hosting supernovae or other transients

Abstract

Type Ia supernovae (SNe Ia) have assumed a fundamental role as cosmological distance indicators since the discovery of the accelerating expansion rate of the universe (Perlmutter et al., 1999; Riess et al., 1998). Correlations between their optical peak luminosity, the decline rate of their light curves and their optical colours allow them to be standardised, reducing their observed r.m.s scatter (e.g. Phillips, 1993; Tripp, 1998). Over a decade ago, the optical peak luminosity of SNe Ia was found to correlate with host galaxy stellar mass, further improving their standardisation (Kelly & others, 2010; Lampeitl et al., 2010; Sullivan et al., 2010). Since then, host galaxy properties have been used in cosmological analyses of SNe Ia (Betoule et al., 2014; Brout et al., 2019; Scolnic et al., 2018) and tremendous effort has gone into findig the property, such as star formation rate (Rigault et al., 2013), that fundamentally drives the correlation between SNe Ia and their host galaxies. Furthermore, it has been noted that the local environment in which the progenitors of SNe Ia evolve is much better at reducing the scatter in estimated distances than the global environment, i.e., the whole galaxy (Kelsey et al., 2021; Roman et al., 2018). Therefore, the study of the effect of environment on SNe Ia is an active field of research and key in future cosmological analyses

Publication
Astronomy & Astrophysics